The invention relates to a public-road device with a hinged cover, in particular a cover constructed in the form of a grid. It applies in particular to devices for capping shafts for draining rainwater or to devices for closing manholes or shafts for inspecting underground mains-water systems, such as manholes in the roadway or pavement.
For reasons of security, and for economic reasons, it is essential that the public-road devices cannot be removed except, where necessary, by competent personnel.
Public-road devices equipped to this end with a means preventing purely manual removal of the cover are already known.
In particular a device for capping access or drain shafts is known, comprising a frame and a cover consisting of a removable grid adapted for being hinged to the frame about an axis extending in the vicinity of one side of the grid, this grid being composed, in the direction of its pivotal axis, of a median part and two side parts bearing parts projecting into seats on the frame which are elastically linked to the median part, conferring upon it an overall deformable structure. The deformability of the framework of the grid is put to advantage in that it is also provided with one or more similarly elastically deformable bars for engaging with snap-fit lugs borne on the frame, in order to prevent all purely manual opening of the manhole allowing the grid to be removed. However, as a result of the overall deformable structure of the grid, removal of the latter remains possible by pinching the two side bars furthest out so as to release their projecting parts from their seat in the frame, by means of makeshift levers.
Anti-theft devices based on the use of an attachment to prevent removal of the cover are similarly known; this is also a disadvantage, because this attachment can be removed by means of a conventional tool and lost.
The object of the invention is to resolve these disadvantages, and to this end relates to a public-road device consisting of a rigid cover hingeably mounted on a frame, the cover comprising two side edges bearing two projecting parts defining an axis of articulation parallel to a hinging border of the cover and engaging with two corresponding cells of the frame at least partially overhung by a wall of the frame, characterised in that the cover also comprises an elastically deformable finger extending parallel to the side edges; the free end of this finger is situated in proximity to the hinging border and is adapted to cooperate with a pressure lug borne by the corresponding hinging edge of the frame in order to permit, by elastic deformation of the finger supported against the lug, positioning of the projecting parts into their respective cells and their removal from them.
Due to this structure, malicious removal and in particular theft of the cover is made difficult, for removal necessitates recourse to a special tool such as a jumper bar or pick-axe.
The public-road device according to the invention may also exhibit one or more of the following characteristics:
The pressure lug has an upper side surface which slopes upwards, and an overhanging lower side surface which, in the closed position of the cover on the frame, co-operates with a corresponding sloping surface of the free end of the elastically flexible finger;
Opposite the lug, the frame exhibits a second pressure lug borne by an end border opposite the hinging border and adapted to co-operate by entering into a snap-fit relationship with the free end of a second flexibly elastic finger borne by the cover;
The second pressure lug and the free end of the second elastically flexible finger have co-operating surfaces forming cams, active in the direction of opening and/or closing of the cover;
The free end of each elastically flexible finger has a recess for a side region of the lug;
The elastically flexible fingers extend perpendicularly to the direction of extent of the hinging projecting parts;
The elastically flexible fingers extend into respective notches of the cover, the free end of each finger terminating in a space manufactured in the corresponding border of the cover;
The cover is a grid;
The cover is made of ductile cast iron; and
The cover is of a generally quadrilateral shape.